55 



Mr. G. F. Dowdeswell. 



The results of intracranial inoculation with virulent medulla, or 

 with the secretion of the salivary glands, of either rabid dog or rabbit, 

 are, as before stated, in all essential respects identical with those that 

 follow subcutaneous inoculation of the same matter — in the small 

 proportion of instances where this is successful — or with those 

 induced experimentally by the bite of a rabid dog, though in these, 

 as described below, the incubation period is of very variable and 

 uncertain duration and much prolonged. 



The first symptom of infection in rabbits is usually, as in the dog, 

 dulness ; the animal sits up with its eyes closed, its head frequently 

 thrown back and inclined to one side. In some few cases, though 

 exceptionally, and not exceeding 3 or 4 per cent., the animal is rest- 

 less and excitable, running round and round its cage, and altogether 

 hypersesthetic ; still more rarely is it aggressive, in one case and one 

 only out of upwards of 200, have I seen a disposition to bite, and in 

 two or three others an inclination to butt. This as in dogs depends no 

 doubt on the disposition of the animal; tame rabbits are usually 

 quiet and familiar enough, but those used to the care of them state 

 that occasionally a normal rabbit in confinement will attempt to bite 

 a hand put into its cage. 



Concurrently with this change, there is a rise of the rectal tempe- 

 rature of about 1° C. from 39*2 — 39'8°, the normal, to between 40° 

 and 41° C, seldom exceeding the latter. This rise is, I believe, 

 invariable, in the regular course of the disease, that is, if not 

 influenced by the action of drugs or other circumstances ; it is very 

 transient, and may occur during the night and easily be unobserved. 

 Usually it lasts about twenty-four hours and then begins to fall more 

 or less quickly, pari passu with the progress of paresis, which is the 

 essential feature of this disease in the rabbit. At first the animal 

 moves slowly and with reluctance, its gait becomes unsteady, the 

 loss of power usually commencing in the hind limbs ; it then entirely 

 loses the use of them ; they are dragged after it if it moves, scram- 

 bling along by its fore-legs ; it lies on its side with its hind- legs stretched 

 out ; respiration which was at first accelerated becomes slow and feeble, 

 the muscles of the trunk and those of the fore limbs are successively 

 paralysed, lastly those of the head and neck, the animal continuing 

 to feed to the very last, frequently dying with hay in its mouth and 

 between its teeth. The motor nerves alone appear to be affected in 

 the rabbit, the reflexes remaining unimpaired to the last. A comatose 

 state always precedes death, which is very gradual and imperceptible, 

 the temperature continuously falling to a very low point. The im- 

 mediate cause of death appears to be paralysis of the respiration, in 

 those animals of which I have witnessed the death. I have found the 

 heart continue to contract for some time afterwards, in one case for 

 nearly half an hour. 



